Application of Taguchi Method for Green Synthesis of Lignin Stabilized Silver Nanoparticles

Lignin is a polyphenolic biomacromolecule, it comprises of numerous functional groups and a
rich aromatic carbon. Polyphenols in lignin are reported as an effective stabilizing agent for
nanoparticles as silver. In this work, lignin extracted from sugarcane bagasse (BG-lignin) was used as
stabilizing and reducing agent for the synthesis of lignin stabilized silver nanoparticles (L-AgNPs).
Physicochemical properties of BG-lignin were investigated by phosphorus-31 NMR spectroscopy,
Fourier-transform infrared spectroscopy and gel permeation chromatography. Three key factors for the
L-AgNPs synthesis including the concentration of silver nitrate (AgNO3), the content of BG-lignin and
the reaction temperature were optimized by using Taguchi method. An L16 (43) orthogonal array was
selected for experimental plan. Confirmation of the formation of L-AgNPs was conducted by UV-vis
spectroscopy and the characteristics of attained L-AgNPs were investigated by scanning electron
microscopy (SEM) and energy dispersive X-ray analysis (EDX). Spherical shape of L-AgNPs with an
average size smaller than 100 nm were obtained from all 16 experiments. The predominant factor for
synthesis L-AgNPs is the content of BG-lignin and the concentration of AgNO3 is the second major
effective factor.